1. Field of the Invention
The present invention relates to a support assembly, and more particularly to a support assembly for a motor shaft for a centrifugal submersible pump and having two support devices to bear the weight of the entire centrifugal submersible pump.
2. Description of Related Art
With reference to FIG. 4, a support device (60) is always mounted on the bottom of a motor assembly (50) of a centrifugal submersible pump to support the motor shaft (520). The conventional support device (60) in accordance with the prior art comprises a base (61), a bearing seat (63) and a thrust journal (62). The base (61) is securely attached to the bottom of a housing (51) of the motor (52). The base (61) is composed of a bottom and a wall extending upward from the periphery of the bottom. A screw (65) with a ball tip is screwed into a threaded hole defined in the bottom of the base (61). The bearing seat (63) is mounted in the base (61) and supported on the screw (65). An indent is defined in the bottom of the bearing seat (63) to receive the ball tip of the screw (65). A thrust bearing (64) is secured to the top of the bearing seat (63). The thrust journal (62) is attached to the free end of the motor shaft (520) and abuts the thrust bearing (62). A key (not shown) and a keyway (not shown) are respectively arranged on the shaft (520) and the thrust journal (62), such that the thrust journal (62) will rotate with the shaft (520) relative to the bearing seat (63).
In operation, when the motor (52) is switched on, the shaft (520) will rotate and drive a pump assembly (not shown) to pump the water. The thrust journal (62) rotates with the shaft (520) relative to the thrust bearing (64). The bearing seat (63) supports the shaft (520) to keep the shaft (520) from axially move due to the weight of the centrifugal submersible pump and the pressure generated when pumping the water.
However, because there is only one support device (60) to support the shaft (520), the thrust journal (62), the bearing seat (63) and the screw (65) bear the weight of the entire centrifugal submersible pump. A huge force will be applied to the thrust journal (62), the bearing seat (63) and the screw (65). The thrust journal (62), the bearing seat (63) and the screw (65) are easily be damaged. The friction between the thrust journal (62) and the thrust bearing (64) is very large, so the thrust bearing (64) is easily worn down. The useful life of the support device (60) is short.
To overcome the shortcomings, the present invention provides an improved support assembly to mitigate or obviate the aforementioned problems.
The main objective of the invention is to provide an improved support assembly for a motor shaft of a centrifugal submersible pump and having two support devices to support the shaft. The support assembly is comprised of a first support device and a second support device. The first support device has a base, a bearing seat with a thrust bearing and a thrust journal. The second support device has a base, a second bearing seat with a thrust bearing and a thrust journal. The first support device and the second support device can support the shaft together. The force applied to each part is reduced, and the friction between each thrust journal and the corresponding thrust bearing is also reduced. The useful life of the support assembly is prolonged.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.